let position = { x: 1, y: 2 };
let dimensions = { width: 100, height: 25 };
let rect = { ...position, ...dimensions };
console.log(rect.x + rect.y + rect.width + rect.height); // 128

let o = Object.create({ x: 1 });
// 扩展操作符只扩展对象的自有属性，不扩展任何继承属性
let p = { ...o };
console.log(p); // {}
